The commit 22a9189fd0 (cdrom: use
kmalloced buffers instead of buffers on stack) is introduced to use
kmalloced buffers for packet commands to avoid stack corruption on non
coherent platforms.
SCSI cdrom uses blk_rq_map_kern, which properly avoids DMA on the
stack by using the bounce buffers. IDE cdrom also has the mechnism to
avoids DMA on the stack. So we don't need this extra complexitiy in
cdrom.c, such as allocating just 8 bytes. The lower layers can handle
it.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tejun Heo <htejun@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
I don't use my IBM email address normally and people can find me in
CREDITS.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
block: Skip I/O merges when disabled
block: add large command support
block: replace sizeof(rq->cmd) with BLK_MAX_CDB
ide: use blk_rq_init() to initialize the request
block: use blk_rq_init() to initialize the request
block: rename and export rq_init()
block: no need to initialize rq->cmd with blk_get_request
block: no need to initialize rq->cmd in prepare_flush_fn hook
block/blk-barrier.c:blk_ordered_cur_seq() mustn't be inline
block/elevator.c:elv_rq_merge_ok() mustn't be inline
block: make queue flags non-atomic
block: add dma alignment and padding support to blk_rq_map_kern
unexport blk_max_pfn
ps3disk: Remove superfluous cast
block: make rq_init() do a full memset()
relay: fix splice problem
Use proc_create()/proc_create_data() to make sure that ->proc_fops and ->data
be setup before gluing PDE to main tree.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Peter Osterlund <petero2@telia.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Neil Brown <neilb@suse.de>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
blk_get_request initializes rq->cmd (rq_init does) so the users don't
need to do that.
The purpose of this patch is to remove sizeof(rq->cmd) and &rq->cmd,
as a preparation for large command support, which changes rq->cmd from
the static array to a pointer. sizeof(rq->cmd) will not make sense and
&rq->cmd won't work.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
If cdrom commands are issued to a scsi drive in most cases the buffer will be
filled via dma. This leads to bad stack corruption on non coherent platforms,
because the buffers are neither cache line aligned nor is the size a multiple
of the cache line size. Using kmalloced buffers avoids this.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Now unregister_cdrom() always returns 0.
Make it return void and update all callers that check the return value.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Use list_head for cdrom_device_info list instead of opencoded
singly list handling.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This patch protects the list of cdrom_device_info by cdrom_mutex
when the file in /proc/sys/dev/cdrom/ is written.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This patch eliminates hardcoded return value of register_cdrom().
It also changes the return value to -EINVAL.
It is more appropriate than -2 (-ENOENT) because it is only
happen invalid usage of register_cdrom() by broken cdrom driver.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This patch removes #ifdef for CONFIG_SYSCTL by defining empty
cdrom_sysctl_register and cdrom_sysctl_unregister when CONFIG_SYSCTL
is not defined.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This patch makes the needlessly global check_for_audio_disc() static.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
WARNING: drivers/cdrom/viocd.o(.text+0x504): Section mismatch in reference from the function .viocd_probe() to the function .init.text:.find_capability()
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
* Move lba_to_msf() and msf_to_lba() to <linux/cdrom.h>
(use 'u8' type instead of 'byte' while at it).
* Remove msf_to_lba() copy from drivers/cdrom/cdrom.c.
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: (197 commits)
sh: add spi header and r2d platform data V3
sh: update r7780rp interrupt code
sh: remove consistent alloc stuff from the machine vector
sh: use declared coherent memory for dreamcast pci ethernet adapter
sh: declared coherent memory support V2
sh: Add support for SDK7780 board.
sh: constify function pointer tables
sh: Kill off -traditional for linker script.
cdrom: Add support for Sega Dreamcast GD-ROM.
sh: Kill off hs7751rvoip reference from arch/sh/Kconfig.
sh: Drop r7780rp_defconfig, use r7780mp_defconfig as kbuild default.
sh: Kill off dead HS771RVoIP board support.
sh: r7785rp: Fix up DECLARE_INTC_DESC() arg mismatch.
sh: r7785rp: Hook up the rest of the HL7785 FPGA IRQ vectors.
sh: r2d - enable sm501 usb host function
sh: remove voyagergx
sh: r2d - add lcd planel timings to sm501 platform data
sh: Add OHCI and UDC platform devices for SH7720.
sh: intc - remove default interrupt priority tables
sh: Correct pte size mismatch for X2 TLB.
...
This patch converts viocd to use blk_end_request interfaces.
Related 'uptodate' arguments are converted to 'error'.
As a result, the interface of internal function, viocd_end_request(),
is changed.
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This patch adds support for the GD-Rom drive, SEGA's proprietary
implementation of an IDE CD Rom for the SEGA Dreamcast. This driver
implements Sega's Packet Interface (SPI) - at least partially. It will
also read disks in SEGA's propreitary GD format.
Unlike previous drivers (which were never in mainline) this uses DMA and
not PIO to read disks. It is a new driver, not a refactoring of old
drivers.
Signed-off by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
The task_struct->pid member is going to be deprecated, so start
using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in
the kernel.
The first thing to start with is the pid, printed to dmesg - in
this case we may safely use task_pid_nr(). Besides, printks produce
more (much more) than a half of all the explicit pid usage.
[akpm@linux-foundation.org: git-drm went and changed lots of stuff]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The binary interface for the cdrom sysctls can't possilby work. So remove the
binary sysctls and update the test for finding out which sysctl table entry we
are dealy with to use the procname and not the ctl_name (which I am removing).
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now we will only have entries in the device tree for the actual existing
devices (including their OS/400 properties). This way viocd.c gets all
the information about the devices from the device tree.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
It was only being used to carry around dma_iommu_ops and vio_iommu_table
which we can use directly instead. This also means that vio_bus_device
doesn't need to refer to them either.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
We don't need to keep a lump of dma coherent memory around for the life
of the module.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Some of the code has been gradually transitioned to using the proper
struct request_queue, but there's lots left. So do a full sweet of
the kernel and get rid of this typedef and replace its uses with
the proper type.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
bsg uses scsi_cmd_ioctl() for some SCSI/sg ioctl
commands. scsi_cmd_ioctl() gets a request queue from a gendisk
arguement. This prevents bsg being bound to SCSI devices that don't
have a gendisk (like OSD). This adds a request_queue argument to
scsi_cmd_ioctl(). The SCSI/sg ioctl commands doesn't use a gendisk so
it's safe for any SCSI devices to use scsi_cmd_ioctl().
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
They are all broken beyond repair. Given that nobody has complained
about them (most haven't worked in 2.6 AT ALL), remove them from the
tree.
A new mitsumi driver that actually works is in progress, it'll get
added when completed.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
- I have unearthed very old bugs in stale drivers that still
used request->cmd as a READ|WRITE int
- This patch is maybe a proof that these drivers have not been
used for a long time. Should they be removed completely?
Drivers that currently do not work for sure:
drivers/acorn/block/fd1772.c | 2 +-
drivers/acorn/block/mfmhd.c | 8 ++++----
drivers/cdrom/aztcd.c | 2 +-
drivers/cdrom/cm206.c | 2 +-
drivers/cdrom/gscd.c | 2 +-
drivers/cdrom/mcdx.c | 2 +-
drivers/cdrom/optcd.c | 2 +-
drivers/cdrom/sjcd.c | 2 +-
Drivers with cosmetic fixes only:
b/drivers/block/amiflop.c
b/drivers/block/nbd.c
b/drivers/ide/legacy/hd.c
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Fix the cdrom_sysctl_info possible buffer overwrite bug. Also
fix the locking of accessing topCdromPtr pointer.
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Fix various bits of obviously-busted code which we're not happening to
compile, due to ifdefs.
Signed-off-by: Yoann Padioleau <padator@wanadoo.fr>
Cc: Andi Kleen <ak@suse.de>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the destroy_dirty_buffers argument from invalidate_bdev(), it hasn't
been used in 6 years (so akpm says).
find * -name \*.[ch] | xargs grep -l invalidate_bdev |
while read file; do
quilt add $file;
sed -ie 's/invalidate_bdev(\([^,]*\),[^)]*)/invalidate_bdev(\1)/g' $file;
done
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix soft lockup with iSeries viocd driver, caused by eventually calling
end_that_request_first() with nr_bytes 0.
Some versions of hald do an SG_IO ioctl on the viocd device which becomes a
request with hard_nr_sectors and hard_cur_sectors set to zero. Passing zero
as the number of sectors to end_request() (which calls
end_that_request_first()) causes an infinite loop when the bio is being freed.
This patch makes sure that the zero is never passed. It only requires some
number larger the the request size the terminate the loop.
The lockup is triggered by hald, interrogating the device.
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The semantic effect of insert_at_head is that it would allow new registered
sysctl entries to override existing sysctl entries of the same name. Which is
pain for caching and the proc interface never implemented.
I have done an audit and discovered that none of the current users of
register_sysctl care as (excpet for directories) they do not register
duplicate sysctl entries.
So this patch simply removes the support for overriding existing entries in
the sys_sysctl interface since no one uses it or cares and it makes future
enhancments harder.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Corey Minyard <minyard@acm.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: David Chinner <dgc@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no need for open files in /proc/sys/XXX to hold a reference count on
the module that provides the file to prevent module unload races. While there
is code active in the module p->used in the sysctl_table_header is
incremented, preventing the sysctl from being unregisted. Once the sysctl is
unregistered it cannot be found. Open files are also not a problem as they
revalidate the sysctl information and bump p->used before accessing module
code.
So setting de->owner is unnecessary, makes for a bad example and gets in my
way of removing ctl_table->de.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With unique binary sysctl numbers setting insert_at_head to override other
sysctl entries is pointless.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there. Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.
To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.
Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm. I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).
Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many struct file_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's a known fact that Windows times out commands after 7 seconds, so
drives generally try and respond if they can before that happens. We
default to 5 seconds, which sometimes is a bit too short.
Jeremy Higdon reported here:
http://lkml.org/lkml/2007/1/1/145
that his drive takes longer than 5 seconds for a "read track
information" command, later confirming that it is about 6.7 seconds.
So just do the sane thing and change the default command timeout to 7
seconds to avoid other surprises.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block:
[PATCH] block: document io scheduler allow_merge_fn hook
[PATCH] cfq-iosched: don't allow sync merges across queues
[PATCH] Fixup blk_rq_unmap_user() API
[PATCH] __blk_rq_unmap_user() fails to return error
[PATCH] __blk_rq_map_user() doesn't need to grab the queue_lock
[PATCH] Remove queue merging hooks
[PATCH] ->nr_sectors and ->hard_nr_sectors are not used for BLOCK_PC requests
[PATCH] cciss: fix XFER_READ/XFER_WRITE in do_cciss_request
[PATCH] cciss: set default raid level when reading geometry fails
The blk_rq_unmap_user() API is not very nice. It expects the caller to
know that rq->bio has to be reset to the original bio, and it will
silently do nothing if that is not done. Instead make it explicit that
we need to pass in the first bio, by expecting a bio argument.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Run this:
#!/bin/sh
for f in $(grep -Erl "\([^\)]*\) *k[cmz]alloc" *) ; do
echo "De-casting $f..."
perl -pi -e "s/ ?= ?\([^\)]*\) *(k[cmz]alloc) *\(/ = \1\(/" $f
done
And then go through and reinstate those cases where code is casting pointers
to non-pointers.
And then drop a few hunks which conflicted with outstanding work.
Cc: Russell King <rmk@arm.linux.org.uk>, Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Steven French <sfrench@us.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch modifies blk_rq_map/unmap_user() and the cdrom and scsi_ioctl.c
users so that it supports requests larger than bio by chaining them together.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
- Eliminate casts to/from void*
- Eliminate checks for conditions that never occur. These typically
fall into two classes:
1) Checking for 'dev_id == NULL', then it is never called with
NULL as an argument.
2) Checking for invalid irq number, when the only caller (the
system) guarantees the irq handler is called with the proper
'irq' number argument.
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.
The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around. On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).
Where appropriate, an arch may override the generic storage facility and do
something different with the variable. On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.
Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions. Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller. A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.
I've build this code with allyesconfig for x86_64 and i386. I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.
This will affect all archs. Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
struct pt_regs *old_regs = set_irq_regs(regs);
And put the old one back at the end:
set_irq_regs(old_regs);
Don't pass regs through to generic_handle_irq() or __do_IRQ().
In timer_interrupt(), this sort of change will be necessary:
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING, regs);
+ update_process_times(user_mode(get_irq_regs()));
+ profile_tick(CPU_PROFILING);
I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().
Some notes on the interrupt handling in the drivers:
(*) input_dev() is now gone entirely. The regs pointer is no longer stored in
the input_dev struct.
(*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
something different depending on whether it's been supplied with a regs
pointer or not.
(*) Various IRQ handler function pointers have been moved to type
irq_handler_t.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
